Selection of Intrinsic Horizontal Connections in the Visual Cortex by Correlated Neuronal Activity

In the visual cortex of the brain, long-ranging tangentially oriented axon collaterals interconnect regularly spaced clusters of cells. These connections develop after birth and attain their specificity by pruning. To test whether there is selective stabilization of connections between those cells that exhibit correlated activity, kittens were raised with artificially induced strabismus (eye deviation) to eliminate the correlation between signals from the two eyes. In area 17, cell clusters were driven almost exclusively from either the right or the left eye and tangential intracortical fibers preferentially connected cell groups activated by the same eye. Thus, circuit selection depends on visual experience, and the selection criterion is the correlation of activity.